VT ThickSat: Technical Challenges for a Testbed for Lightweight Deployable Space Structures

This paper describes challenges and lessons learned throughout the concept, design, assembling, integrating, and testing for hardware and software of Virginia Tech (VT) ThickSat, a testbed for lightweight deployable space structures designed by engineering students at Virginia Tech. The project started in 2017 as part of the senior design undergraduate team at VT in collaboration with the Virginia Space and Near Space Launch Systems. The project's mission is to prove passive deployment of a spring table boom in low earth orbit, obtain deployment confirmation and transmit a picture back to Earth. To develop this project, over 25 different undergraduate and graduate students participated. In this process, they reached many breaking points and tough technical decisions. Throughout its development, the mission faced significant design reviews. It a maximum allowed 100mA power draw from the bus and a top 150 kiloByte packet size transmission for its entire 28-hour mission. The resulting design can be replicated and easily scalable for much more significant roles under the same requirements. This paper builds the challenges and lessons learned from the redesign, assembling, integrating, and testing of hardware and software. Furthermore, it describes the restrictive design characteristics of the ThinSat program in detail, which led the students to come with smart solutions for its many different design interactions. The ThickSat solution includes a custom low power PCB for an STM32 microcontroller, a servo actuated release mechanism, and a versatile chassis for the ThinSat Program. This study comprises an analytical point of view from the senior monitoring group and other engineers from the Center for Space Science and Engineering Research, known as (Space@VT), summarizing the experience from a student-led ThinSat project. The outcome of this paper is to share an experience that leads to bolster future SmallSat missions at Virginia Tech and other institutions.